Scientists & Clinicians

Learn about our program of research

Our research program is designed to understand the typical and atypical development of the human visual system. In our work funded by the National Eye Institute since 2003, we first completed a series of studies of typical retinal image quality during infancy and early childhood (Wang & Candy, 2005; Tondel & Candy, 2007 & 2008; Candy & Bharadwaj, 2007; Wang, Candy, Teel & Jacobs, 2008; Candy, Wang & Ravikumar 2009; Wang & Candy, 2010, Bharadwaj et al, 2011).  These studies demonstrated that, although infants have limited spatial vision, they are typically able to generate accommodative responses to approximately 0.5D of retinal defocus with a latency on the order of 0.5s by 3 months of age.   They also have relatively mature higher order monochromatic aberrations with chromatic aberration that is consistent with the their immature eye size.

In a second series of studies we then started to look at the relationship between retinal image quality in the two eyes of typically developing children (Bharadwaj & Candy, 2008, 2009 & 2010), children with atypical amounts of hyperopia who are at risk for strabismus (Candy et al, 2012; Candy 2012;  Babinsky & Candy, 2013), and children with amblyopia (Barrett et al, 2013; Manh et al, 2015; Chen et al, 2018).  These studies have contributed to the literature examining the conflicting motor tasks that the developing visual system must undertake and have started to determine which young hyperopes are at the greatest risk for esotropia.

Our most recent work has concentrated on understanding how infants and children maintain eye alignment in the presence of the increased accommodative demand that results from their hyperopic refractive state (Babinsky et al, 2015, 2016; Sreenivasan et al, 2016; Seemiller et al, 2016, 2018a & b; Wu et al 2016, Troyer et al, 2017).  We have been attempting to understand how motor binocular function first develops in early infancy, and how different redundant components of accommodative and vergence responses are combined during visual development.  This work is discussed in combination in a recent review in the Annual Review of Vision Science (Candy, 2019).

Our recent lab publications (Full PubMed listing)

  1. Associations between visual function and magnitude of refractive error for emmetropic to moderately hyperopic 4- and 5-year-old children in the Vision in Preschoolers – Hyperopia in Preschoolers Study.  Ciner EB, Kulp MT, Pistilli M, Ying GS, Maguire M, Candy TR, Moore B, Quinn G; Vision In Preschoolers – Hyperopia In Preschoolers (VIP-HIP) Study Group†.  Ophthalmic Physiol Opt. 2021 May;41(3):553-564. doi: 10.1111/opo.12810. Epub 2021 Mar 27.
  2. The relationship between reflex eye realignment and the percept of single vision in young children.  Meier K, Lundell DL, Seemiller ES, Giaschi D, Wilcox LM, Candy TR.  Sci Rep. 2021 Jan 11;11(1):375. doi: 10.1038/s41598-020-78636-0.
  3. The Importance of the Interaction Between Ocular Motor Function and Vision During Human Infancy.  Candy, TR. Annu Rev Vis Sci. 2019 Sep 15;5:201-221. doi: 10.1146/annurev-vision-091718-014741.
  4. Calibration of the PlusOptix PowerRef 3 with change in viewing distance, adult age and refractive error. Ghahghaei S, Reed O, Candy TR, Chandna A. Ophthalmic Physiol Opt. 2019 Jul;39(4):253-259. doi: 10.1111/opo.12631.
  5. The gaze stability of 4- to 10-week-old human infants. Seemiller ES, Port NL, Candy TR. J Vis 2018 Aug1;18(8);15. doi: 10.1167/18.8.15.
  6. Human infants can generate vergence responses to retinal disparity by 5 to 10 weeks of age. Seemiller ES, Cumming BG, Candy TR. J Vis. 2018 Jun 1;18(6):17. doi: 10.1167/18.6.17.
  7. Longitudinal Evaluation of Accommodation During Treatment for Unilateral Amblopia. Chen AM, Manh V, Candy TR. Invest Ophthalmol Vis Sci. 2018 Apr 1;59(5):2187-2196. doi:10.1167/iovs.17-22990.
  8. Two-dimensioinal simulation of eccentric photorefraction images for ametropes: factors influencing the measurement. Wu Y, Thibos LN, Candy TR. Ophthalmic Physiol Opt. 2018 Jul;38(4):432-446. doi: 10.1111/opo.12563. Epub 2018 May 7.
  9. The heterophoria of 3-5 year old children as a function of viewing distance and target type. Troyer ME, Sreenivasan V, Peper TJ, Candy TR.Ophthalmic Physiol Opt. 2017 Jan;37(1):7-15. doi: 10.1111/opo.12342. Epub 2016 Dec 5.
  10. Adaptation of horizontal eye alignment in the presence of prism in young children. Wu Y, Sreenivasan V, Babinsky EE, Candy TR. J Vis. 2016 Aug 1;16(10):6. doi: 10.1167/16.10.6
  11. Objective Measurement of Fusional Vergence Ranges and Heterophoria in Infants and Preschool Children. Sreenivasan V, Babinsky EE, Wu Y, Candy TR Invest Ophthalmol Vis Sci. 2016 May 1;57(6):2678-88. doi: 10.1167/iovs.15-17877
  12. Vergence Adaptation to Short-Duration Stimuli in Early Childhood. Babinsky E, Sreenivasan V, Candy TR. Invest Ophthalmol Vis Sci. 2016 Mar;57(3):920-7. doi: 10.1167/iovs.15-17767
  13. Sensitivity of vergence responses of 5- to 10-week-old human infants. Seemiller ES, Wang J, Candy TR. J Vis. 2016;16(3):20. doi: 10.1167/16.3.20
  14. Near Heterophoria in early childhood. Babinsky E, Sreenivasan V, Candy TR. Invest Ophthalmol Vis Sci. 2015 Jan 29;56(2): 1406-15. doi: 10.1167/iovs.14-14649.
  15. Accommodative performance of children with unilateral amblyopia. Manh V, Chen AM, Tarczy-Hornoch K, Cotter SA, Candy TR. Invest Opthalmol Vis Sci. 2015 Jan 27;56(2):1193-207. doi:10.1167/iovs.14-14948.
  16. Why do only some hyperopes become strabismic? Babinsky E, Candy TR Invest Opthalmol Vis Sci. 2013 Jul 24;54(7):4941-55. doi:10.1167/iovs. 12-10670. Review.
  17. The relationship between anisometropia and amblyopia. Prog Retin Eye Res. Barrett BT, Bradley A, Candy TR 2013 Sep;36:120-58. doi: 10.1016/j.preteyeres.2013.05.001. Epub 2013 Jun 15. Review.
  18. Empirical variability in the calibration of slope-based eccentric photorefraction. Bharadwaj SR, Sravani NG, Little JA, Narasaiah A, Wong V, Woodburn R, Candy TR. J Opt Soc Am A Opt Image Sci Vis. 2013 May 1;30(5):923-31. doi: 10.1364/JOSAA.30.000923.
  19. Which hyperopic patients are destined for trouble? Candy TR. Journal of AAPOS. 2012 Apr;16(2):107-9. doi: 10.1016/j.jaapos.2012.02.004
  20. The accommodative lag of the young hyperopic patient. Candy TR, Gray KH, Hohenbary CC, Lyon DW. Invest Opthalmol Vis Sci. 2012 Jan 17;53(1):143-9. doi:10.1167/iovs.11-8174.
  21. Pupil responses to near visual demand during human visual development. Bharadwaj SR, Wang J, Candy TR. J Vis. 2011 Apr 11;11(4):6. doi: 10.1167/11.4.6.
  22. Adult discrimination performance for pediatric acuity test optotypes. Candy TR, Mishoulam SR, Nosofsky RM, Dobson V. Invest Ophthalmol Vis Sci. 2011 Jun 16;52(7):4307-13. doi: 10.1167/iovs.10-6391.
  23. The effect of lens-induced anisometropia on accommodation and vergence during human visual development. Bharadwaj SR, Candy TR. Invest Ophthalmol Vis Sci. 2011 Jun 1;52(6):3595-603. doi: 10.1167/iovs.10-6214.
  24. Orientaton tuning in the visual cortex of 3-month-old human infants. Baker TJ, Norcia AM, Candy TR. Vis Res. 2011 Mar 2;51(5):470-8. doi: 10.1016/j.visres.2011.01.003. Epub 2011 Jan 12.
  25. The sensitivity of the 2- to 4-month-old human infant’s accommodation system. Wang J, Candy TR. Invest Ophthalmol Vis Sci. 2010 Jun;51(6):3309-17. doi: 10.1167/iovs.09-4667. Epub 2009 Dec 30.
  26. Accommodative and vergence responses to conflicting blur and disparity stimuli during development. Bharadwaj, SR, Candy, TR. J Vis. 2009 Oct 5;9(11):4.1-18. doi: 10.1167/9.11.4.
  27. Retinal image quality and postnatal visual experience during infancy. Candy TR, Wang J, Ravikumar S. Optom Vis Sci.  2009 Jun;86(6) E566-571. doi: 10.1097/OPX.0b013e3181a76e6f. Review.
  28. Cues for the control of ocular accommodation and vergence during postnatal human development. Bharadwaj SR, Candy TR. J Vis. 2008 Dec 22;8(16):14.1-16. doi: 10.1167/8.16.14.
  29. Longitudinal chromatic aberration of the human infant eye. Wang J, Candy TR, Teel DFW, Jacobs RJ. J Opt Soc Am A Opt Image Sci Vis. 2008 Sep;25(9): 2263-70.
  30. Accommodation and vergence latencies in human infants. Tondel GM, Candy TR. Vision Res. 2008 Feb;48(4):564-76. doi: 10.1016/j.visres.2007.11.016. Epub 2008 Jan 15.
  31. The stability of steady state accommodation in human infants. Candy TR, Bharadwaj SR. J Vis. 2007 Aug 17;7(11):4.1-16.
  32. Human infants’ accommodation responses to dynamic stimuli. Tondel GM, Candy TR. Invest Opthalmol Vis Sci. 2007 Feb:48(2):949-956.
  33. Validation of the PowerRefractor for measuring human infant refraction. Blade PJ, Candy TR. Optom Vis Sci. 2006 Jun;83(6):346-53.
  34. Higher-order monochromatic aberrations of the human infant eye. Wang J, Candy TR. J Vis. 2005 Jun 23;5(6):543-555.
  35. Probing the causes of visual acuity loss in patients diagnosed with functional amblyopia. Barrett BT, Candy TR, McGraw PV, Bradley A. Ophthalmic Physiol Opt. 2005 May;25(3):175-8.

Guest editorials:

  • Barrett, TB., Candy, TR, McGraw, PV & Bradley, A. (2005) Probing the causes of visual acuity loss in patients diagnosed with functional amblyopia. Guest Editorial in Ophthalmic & Physiological Optics. 25: 175-78.
  • Mutti DO, Candy R, Cotter SA, Haegerstrom-Portnoy G. (2007) Infant and child hyperopia. Guest Editorial in Optometry & Vision Science. Feb;84(2):80.
  • Dobson V, Candy TR, Hartmann EE, Mayer DL, Miller JM, Quinn GE (2009) Infant and child vision research present status and future directions Guest editorial in Optometry & Vision Science, 86, 559-560.

Book Chapters:

Candy TR ‘Development of the Visual System’ in ‘ Visual Development, Diagnosis, and Treatment of the Pediatric Patient’. Ed. Duckman, R. Lippincott, Williams & Wilkins. Spring 2006.

Candy TR ‘Development of the Visual System’ in “Visual Development, Diagnosis, and Treatment of the Pediatric Patient.” Second Edition. Ed. Schnell PH, Duckman RH, Taub MB. Wolters Kluwer Health/Lippincott Williams & Wilkins. 2020.

Candy TR, Aslin RN ‘Visual Sensory Development’ in “Encyclopedia of Infant and Early Childhood Development.” Second Edition. Ed. Benson JB. Elsevier 2020.

Other Visitor Pages

Clinical Care

More Resources

Our Research
Who Are We?
Related Links

Funding supporting the Lab

National Eye Institute:
ROI EY014460 Candy (PI) 2003-2022
Accommodation and Defocus in the
Infant Visual System

Fight For Sight PostDoctoral Fellowships:
Shrikant Bharadwaj 2008-2009
Vidhyapriya Sreenivasan 2014-2015


Lab Phone number: 812-855-4959
Lab Email Account: [email protected]